This time I will show you how to use koa2 to build a WeChat third-party public platform. What are the precautions for using koa2 to build a WeChat third-party public platform. The following is a practical case, let's take a look.

Before writing, I want to talk about koa first. Compared with express, koa is much better in terms of execution process and components. koa itself does not provide too many extensions, but it is convenient to build extensions. It allows you to play freely and execute code in parallel like writing other languages. If promises free up cumbersome callbacks, then when writing web applications in koa, by combining different generators, you can avoid repeating cumbersome callback functions Nesting, and greatly improves the efficiency of error handling. koa does not bind any middleware in the kernel method. It only provides a lightweight and elegant function library, making it easy to write web applications. The natural asynchronous processing process of nodejs makes it very suitable for frequent transactions such as WeChat public accounts. Message interaction, coupled with pm2's multi-process management, can be said to have largely satisfied the message forwarding interaction of large accounts and the internal red envelope gameplay of public accounts.

When using koa2 to build a WeChat third-party public platform, the first thing to solve is how to obtain the XML stream returned by WeChat and how to return the corresponding XML body to WeChat.
Since koa itself is not a framework, so thanks to the many middlewares on the Internet, I built a framework similar to express. This framework has been open source. For details, please see my git address: https:// github.com/yxz1025/koa-lana, all WeChat messages are in this framework, please download it yourself!

Okay, first of all, let’s take a look at how to get the xml stream returned by WeChat:

======tool.js=====
//截獲微信返回的xml流文件
const?Promise?=?require('bluebird');
//普通post流轉(zhuǎn)化為promise
var?Tool?=?{
??convertPost:?function(req)?{
????let?post_data?=?"";
????return?new?Promise(function(resolve,?reject){
??????req.on('data',?function(chunk)?{
????????post_data?+=?chunk;
??????});
??????req.on('end',?function()?{
????????resolve(post_data);
??????});
????});
??},
};
module.exports?=?Tool;
=====weichat.js======
//微信響應(yīng)主體文件
const?router?=?require('koa-router')();
const?parseMessage?=?require('../common/parseMessage');
const?config?=?require('../config');
const?WXBizMsgCrypt?=?require('wechat-crypto');
const?middleware?=?require('../model/middleware');
const?validator?=?require('validator');
const?Aes?=?require('../common/aes');
const?Tool?=?require('../common/tool');
const?cryptor?=?new?WXBizMsgCrypt(config.component_config.token,?config.component_config.key,?config.component_config.component_appid);
//第三方授權(quán)路徑?/:appid/callback??/wechat/100234/callback
router.post('/:appid/callback',?async?function(ctx,?next)?{
??let?post_data?=?"";
??let?req?=?ctx.req;
??post_data?=?await?Tool.convertPost(req);
??let?xml?=?parseMessage(post_data);
??let?signature?=?cryptor.getSignature(ctx.query.timestamp,?ctx.query.nonce,?xml.encrypt);
??if?(ctx.query.msg_signature?!=?signature)?{
????ctx.body?=?'Auth?failed!';?//?指紋碼不匹配時返回錯誤信息，禁止后面的消息接受及發(fā)送
??}
??let?message?=?middleware.decryptXml(xml);
??let?appid?=?ctx.params.appid;
??message.appId?=?appid;
??//發(fā)送消息隊列
??switch?(message.msgType)?{
????case?'text':
??????//測試
??????if?(message.toUserName?==?"gh_3c884a361561")?{
????????if?(message.content?==?"TESTCOMPONENT_MSG_TYPE_TEXT")?{
??????????let?text?=?middleware.text(message,?message.content?+?"_callback");
??????????let?reply?=?middleware.encryptXml(text);
??????????return?ctx.body?=?reply;
????????}
????????let?content?=?message.content;
????????if?(content.indexOf("QUERY_AUTH_CODE")?!=?-1)?{
??????????ctx.body?=?"";
??????????let?code_li?=?content.split(":");
??????????await?middleware.customSend(message.fromUserName,?code_li[1]);
??????????return;
????????}
??????}
??????let?keywords?=?validator.trim(message.content).toLowerCase();
??????let?member_config?=?await?middleware.getMemberConfig(message.toUserName,?keywords);
??????if?(!member_config)?{
????????await?middleware.sendMnsQuene(message);
????????return?ctx.body?=?"success";
??????}else{
?????????//匹配成功
????????message.packetsId?=?parseInt(member_config.hongbaoId);
????????message.keywords?=?keywords;
????????await?middleware.sendMnsQuene(message);
????????let?data?=?{
??????????title:?member_config.news_title?||?'點我領(lǐng)紅包',
??????????description:?member_config.description?||?'第一輪紅包雨開始了,手快有,手慢無！',
??????????picurl:?member_config.picurl?||?'http://7xqomp.com2.z0.glb.qiniucdn.com/17269743.png'
????????};
????????let?key?=?{
??????????fromUserName:?message.fromUserName,
??????????toUserName:?message.toUserName,
??????????keywords:?keywords,
??????????appId:?appid
????????};
????????key?=?JSON.stringify(key);
????????key?=?Aes.encypt(key);
????????key?=?Aes.base64_encode(key);
????????//獲取授權(quán)域名
????????let?auth_url?=?await?middleware.packetDomain();
????????data.url?=?"http://"?+?appid?+?"."?+?auth_url?+?"/redPackets/koulin?key="?+?key;
????????let?news?=?middleware.news(message,?[data]);
????????let?reply?=?middleware.encryptXml(news);
????????ctx.body?=?reply;?
????????return;???????
??????}
??????break;
????case?'event':
??????await?middleware.sendMnsQuene(message);
??????//測試專用
??????if?(message.toUserName?==?"gh_3c884a361561")?{
????????let?text?=?middleware.text(message,?message.event?+?"from_callback");
????????let?reply?=?middleware.encryptXml(text);
????????ctx.body?=?reply;
????????return;
??????}
??????break;
????default:
??????await?middleware.sendMnsQuene(message);
??????ctx.body?=?"success";
??????return;
??};
});
module.exports?=?router;

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related topics on the PHP Chinese website article!

Recommended reading:

How to operate Koa2 WeChat public account development and build a local development and debugging environment

How to operate Koa2 WeChat public account implementation Message management

The above is the detailed content of How to use koa2 to build a WeChat third-party public platform. For more information, please follow other related articles on the PHP Chinese website!